As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option is an information handling system. An information handling system generally processes, compiles, stores, or communicates information or data for business, personal, or other purposes. Technology and information handling needs and requirements can vary between different applications. Thus information handling systems can also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information can be processed, stored, or communicated. The variations in information handling systems allow information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems can include a variety of hardware and software resources that can be configured to process, store, and communicate information and can include one or more computer systems, graphics interface systems, data storage systems, networking systems, and mobile communication systems. Information handling systems can also implement various virtuatized architectures. Data and voice communications among information handling systems may be via networks that are wired, wireless, or some combination.
One subsystem of an information handling system is a storage subsystem. A storage subsystem can be implemented using a redundant array of inexpensive disks (RAID). A RAID storage subsystem comprises a RAID controller and a disk group (DG). The DG comprises a plurality of physical disks (PDs) configured to store information which is presented to the information handling system as being stored on a virtual disk (VD) even though the storage of the information is distributed among the PDs. A PD of the PDs may be replaced by a replacement PD through the use a member replacement feature of the RAID controller. In existing RAID storage subsystems, a PD cannot be replaced with a replacement PD of lesser information storage capacity than the capacity of the PD having the least capacity in the DG even though the replacement PD may be of greater capacity than the used space of PDs in the DG.
For example, a RAID level 0 DG may comprise two PDs, wherein one has a 100 gigabyte (GB) capacity and another has a 200 GB capacity, and two VDs, wherein one has a capacity of 40 GB and another has a capacity of 60 GB. In such an example, the used space in each PD is only 50 GB (i.e., 20 GB+30 GB in each PD). If an attempt is made to replace the 200 GB PD with a replacement PD of the same drive type and of a capacity less than the least capacity of any PD in the DG (i.e., 100 GB) but greater than the used space of each PD in the DG (i.e., 50 GB), then the RAID controller does not allow for member replacement, even though the actual used space in each PD is only 50 GB.
As a RAID level 0 VD does not provide data redundancy, if the RAID controller detects a predictive failure indication fir one of the RAID level 0 PDs in the DG, then it is crucial for the customer to change the indicated PD as soon as possible with a replacement PD provided its replacement PD capacity is greater than or equal to the capacity of whichever PD has the smallest capacity of any PD in the DG. Otherwise, drive failure of the indicated PD storing information for the RAID level 0 VD results in complete data loss. If no replacement PD having a capacity equal to or greater than the capacity of the PD having the least capacity among the PDs of the DG is available, then the RAID controller does not allow for member replacement even if a PD of lesser capacity is available. Thus, data loss may result because of unavailability of a replacement PD of adequate capacity to satisfy the requirements of the RAID controller. While the above example is described with respect to RAID level 0, such a drawback can apply to RAID subsystems of other RAID levels such as RAID levels 1, 5, 6, 10, 50, and 60.